Mass flow meters conforming to this type include: at least one vibrating measuring tube for guiding a medium whose flow rate is to be measured; at least one exciter for bringing about vibrations in the measuring tube; at least two sensors for detecting the vibrations in the measuring tube, and for outputting first and second sensor signals that depend upon the vibrations; and at least one operating and evaluating unit for driving the exciter, to detect the sensor signals and to determine a mass flow measurement value on the basis of a phase difference between the sensor signals that is, on a first approximation, proportional to the mass flow.
It is known that the phase difference or time difference of the sensor signals has a cross-sensitivity to the viscosity of the medium. WO 2011/068500 A1, EP 1 659 377 A1, and WO 2000/36379 A1 describe mass flow meters whose operating and evaluating unit is configured to determine the viscosity of the measuring medium and to carry out a correction of this cross-sensitivity as a function of the Reynolds number. Although these approaches can produce useful results for Reynolds numbers greater than 500, they leave much to be desired for smaller Reynolds numbers. With increasing miniaturization in particular, there is therefore a need for measurement recordings that can provide a remedy in this regard. Therefore, it is the aim of the present invention to provide such a sensor and a corresponding method.